Hydraulic Brake Booster Pump: Service and Repair

Removing and installing pre-boost pump DSC3

Note: After completing work:
- Connect brake fluid changer.
- Activate precharging pump with Diagnosis and Information System.
- Vent front-axle circuit.
Before beginning work: Draw off brake fluid.





Remove expansion rivets (1) and release screws (2). Remove wheel arch.





Release screw.

Installation:

All screws to precharging pump and holder 8 Nm





Unfasten plug connection and disconnect.
Detach brake lines.

Caution:
Brake fluid may emerge.
Do not mix up brake lines.

Installation:
Line connections (see designation on precharging pump):
HZ: Line to tandem brake master cylinder
BA: Line to brake fluid expansion tank
- Brake hose couplings
- M10 x 1 18 ± 1 Nm
- M12 x 1 18 ± 1 Nm

Remove precharging pump from rubber mounts.





Release screws, convert protective cap (1) and holder (2).
- All screws to precharging pump and holder 8 Nm